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can-utils
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slcand : added new commandline option to support direct assignment of a CAN 

netdevice name to the given tty (by renaming the created netdevice).

Signed-off-by: Robert Haddon <robert.haddon@cirrascale.com>
Signed-off-by: Oliver Hartkopp <socketcan@hartkopp.net>
pull/7/head
Oliver Hartkopp 2010-11-19 19:52:39 +00:00
parent d1efcd1d75
commit 33ff70f940
1 changed files with 50 additions and 9 deletions
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59
slcand.c
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@ -52,6 +52,7 @@
#include <pwd.h> #include <pwd.h>
#include <signal.h> #include <signal.h>
#include <sys/ioctl.h> #include <sys/ioctl.h>
#include <net/if.h>
/* default slcan line discipline since Kernel 2.6.25 */ /* default slcan line discipline since Kernel 2.6.25 */
#define LDISC_N_SLCAN 17 #define LDISC_N_SLCAN 17
@ -67,10 +68,10 @@
void print_usage(char *prg) void print_usage(char *prg)
{ {
fprintf(stderr, "\nUsage: %s tty\n\n", prg); fprintf(stderr, "\nUsage: %s tty [name]\n\n", prg);
fprintf(stderr, "Example:\n"); fprintf(stderr, "Example:\n");
fprintf(stderr, "%s ttyUSB1\n", prg); fprintf(stderr, "%s ttyUSB1\n", prg);
fprintf(stderr, "%s ttyS0\n", prg); fprintf(stderr, "%s ttyS0 can0\n", prg);
fprintf(stderr, "\n"); fprintf(stderr, "\n");
exit(EXIT_FAILURE); exit(EXIT_FAILURE);
} }
@ -91,7 +92,7 @@ static void child_handler (int signum)
} }
} }
static void daemonize (const char *lockfile, char *tty) static void daemonize (const char *lockfile, char *tty, char *name)
{ {
pid_t pid, sid, parent; pid_t pid, sid, parent;
int lfp = -1; int lfp = -1;
@ -124,7 +125,7 @@ static void daemonize (const char *lockfile, char *tty)
struct passwd *pw = getpwnam (RUN_AS_USER); struct passwd *pw = getpwnam (RUN_AS_USER);
if (pw) if (pw)
{ {
syslog (LOG_NOTICE, "setting user to " RUN_AS_USER); //syslog (LOG_NOTICE, "setting user to " RUN_AS_USER);
setuid (pw->pw_uid); setuid (pw->pw_uid);
} }
} }
@ -207,17 +208,26 @@ static void daemonize (const char *lockfile, char *tty)
int main (int argc, char *argv[]) int main (int argc, char *argv[])
{ {
char *tty; char *tty = NULL;
char *ttypath; char *ttypath;
char const *devprefix = "/dev/"; char const *devprefix = "/dev/";
char *name = NULL;
char buf[IFNAMSIZ+1];
/* Initialize the logging interface */ /* Initialize the logging interface */
openlog (DAEMON_NAME, LOG_PID, LOG_LOCAL5); openlog (DAEMON_NAME, LOG_PID, LOG_LOCAL5);
/* See how we're called */ /* See how we're called */
if (argc != 2) if (argc == 2) {
print_usage(argv[0]);
tty = argv[1]; tty = argv[1];
} else if (argc == 3) {
tty = argv[1];
name = argv[2];
if (strlen(name) > IFNAMSIZ-1)
print_usage(argv[0]);
} else {
print_usage(argv[0]);
}
/* Prepare the tty device name string */ /* Prepare the tty device name string */
char * pch; char * pch;
@ -230,22 +240,53 @@ int main (int argc, char *argv[])
syslog (LOG_INFO, "starting on TTY device %s", ttypath); syslog (LOG_INFO, "starting on TTY device %s", ttypath);
/* Daemonize */ /* Daemonize */
daemonize ("/var/lock/" DAEMON_NAME, tty); daemonize ("/var/lock/" DAEMON_NAME, tty, name);
/* Now we are a daemon -- do the work for which we were paid */ /* Now we are a daemon -- do the work for which we were paid */
int fd; int fd;
int ldisc = LDISC_N_SLCAN; int ldisc = LDISC_N_SLCAN;
if ((fd = open (ttypath, O_WRONLY | O_NOCTTY )) < 0) { if ((fd = open (ttypath, O_WRONLY | O_NOCTTY )) < 0) {
syslog (LOG_NOTICE, "failed to open TTY device %s\n", ttypath);
perror(ttypath); perror(ttypath);
exit(1); exit(1);
} }
/* set slcan like discipline on given tty */
if (ioctl (fd, TIOCSETD, &ldisc) < 0) { if (ioctl (fd, TIOCSETD, &ldisc) < 0) {
perror("ioctl"); perror("ioctl TIOCSETD");
exit(1); exit(1);
} }
/* retrieve the name of the created CAN netdevice */
if (ioctl (fd, SIOCGIFNAME, buf) < 0) {
perror("ioctl SIOCGIFNAME");
exit(1);
}
syslog (LOG_NOTICE, "attached TTY %s to netdevice %s\n", ttypath, buf);
/* try to rename the created netdevice */
if (name) {
struct ifreq ifr;
int s = socket(PF_INET, SOCK_DGRAM, 0);
if (s < 0)
perror("socket for interface rename");
else {
strncpy (ifr.ifr_name, buf, IFNAMSIZ);
strncpy (ifr.ifr_newname, name, IFNAMSIZ);
if (ioctl(s, SIOCSIFNAME, &ifr) < 0) {
syslog (LOG_NOTICE, "netdevice %s rename to %s failed\n", buf, name);
perror("ioctl SIOCSIFNAME rename");
exit(1);
} else
syslog (LOG_NOTICE, "netdevice %s renamed to %s\n", buf, name);
close(s);
}
}
/* The Big Loop */ /* The Big Loop */
while (1) { while (1) {
sleep(60); /* wait 60 seconds */ sleep(60); /* wait 60 seconds */